A new multidrug chemotherapy regimen significantly prolongs the survival in patients with lung cancer. If this new regimen is widely implemented, what changes in the prevalence and incidence of lung cancer would you expect?

Question

A new multidrug chemotherapy regimen significantly prolongs the survival in patients with lung cancer.  If this new regimen is widely implemented, what changes in the prevalence and incidence of lung cancer would you expect?

Quizplus · Accepted Answer

It is important to understand the difference between prevalence and incidence, the two basic measures of disease occurrence. Incidence is the measure of new cases, the rapidity with which they are diagnosed. Prevalence is the measure of the total number of cases at a particular point in time. Incidence answers the question: how many new cases of the disease developed in a population during a particular period of time? Prevalence answers the question: how many cases of the disease exist in a population at a particular point in time? The relationship between prevalence and incidence can be expressed as: Prevalence = (Incidence) x (Time) Prevalence = (Incidence) x (Time) The incidence of a disease is not changed by any kind of treatment, because the disease has already occurred when treatment is started. On the other hand, the prevalence may be affected by treatment of the disease. In this case, treatment of an acute and rapidly fatal disease (e.g., lung cancer) prolonged the survival of patients; however, such treatment did not cure the disease. This will result in more people having the said disease at one point in time; hence, the prevalence will increase. (Choices A, B and E) The incidence of a disease is not affected by the treatment. (Choice D) This statement is not correct because a prolonged time of survival will increase the prevalence. Educational objective: Know the difference between incidence and prevalence. Incidence is the measure of new cases, the rapidity with which they are diagnosed. Prevalence is the measure of the total number of cases at a particular point in time.

A New Multidrug Chemotherapy Regimen Significantly Prolongs the Survival in Patients